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Finding the Fourth Proportional to 1,020.39, 1,407.54 and 688.89

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Solution

The fourth proportional to 1,020.39, 1,407.54 and 688.89 is: 950.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,020.39 : 1,407.54 = 688.89 : x
  2. Step 2: Convert to fraction form
    1,020.39/1,407.54 = 688.89/x
  3. Step 3: Cross multiply
    1,020.39x = 1,407.54 × 688.89
  4. Step 4: Simplify right side
    1,020.39x = 969,640.23
  5. Step 5: Solve for x
    x = 969,640.23/1,020.39
  6. Step 6: Final answer
    x = 950.26

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.